The present invention relates generally to roller apparatus, and more particularly to roller apparatus for rolling a flexible webbing material such as pull-down window shades, maps, charts or the like.
In the past, such window shades, maps, charts and the like have generally been provided with rollers of the spring-loaded type. The flexible webbing is generally firmly attached to the spring-loaded roller, as by tacking or stapling, for example. Moreover, such rollers are constrained to rolling up the attached webbing in a single direction. Accordingly, should the roller malfunction, the shade or chart generally must be carefully removed to effect repair or replacement of the roller. Additionally, such rollers generally do not permit the chart or window shade attached thereto to be readily removed and replaced with a different chart or shade.
Due to the above-mentioned directional constraint of such rollers, the chart or shade carried upon such a roller may not be reversed so as to reveal both sides thereof to a fixed observer. However, such reversibility is both useful and desirable in the case of window shades or the like having different patterns or finishes at either side thereof. For example, window shades are available having a reflective surface at one side thereof and a semi-transparent, generally tinted surface at the other side thereof. Accordingly, it is often desirable during warm summer months to place the reflective surface toward a window to reflect the sunlight back outwardly and thereby aid in cooling the building. On the other hand, during winter months, it is often desirable to reverse such a window shade so as to admit some amount of sun, and further tend to reflect the heat within the building back inwardly. Such a window shade cannot be reversed in this fashion when attached to a conventional spring-loaded roller device.
In the case of charts, maps or the like, which are generally printed or bear information on but one side, conventional rollers permit rolling up thereof in but a single direction, generally with the printed side out. Accordingly, most maps, charts and the like bear a dust cover device attached to the free end thereof which may be rolled and secured around the chart or map when fully rolled on the roller to protect the chart or map from dirt, dust or the like. However, provision of a bidirectional roller device can eliminate the need for such a dust cover, by permitting rolling of the chart or map with the unprinted side outwardly, to serve as protection for the printed side thereof. Further in this regard, rolling in either direction also tends to discourage the chart or map from taking a set or curl in response to being carried for periods of time rolled up on the roller.